Social engineering
Left-anarchists can not realistically change the hierarchy in male / female relationships without some heavy social engineering requiring heavy coercion.
I don’t think that the empirical evidence points very strongly toward the conclusion that anti-sexism would require a continuous process of “heavy social engineering.” (It would take heavy social engineering to get from where we are to an anti-sexist society, but as I see it, that’s because it took heavy social engineering to get to where we are, not because there is some perennial in-born basis for structuring social relationships in terms of sex-class.)
But suppose you’re right. Suppose there is some in-born, perennial basis that will keep asserting itself in favor of hierarchical relationships structured by sex.
Does it follow that any attempt to combat that through “heavy social engineering” will require “heavy coercion?” Only if all forms of social engineering are coercive. But they’re not. For example, mass literacy is only possible through heavy and continuous “social engineering” aimed at teaching children how to do something quite difficult over a period of years. But does mass literacy require coercion? Not as far as I can see.
Does it follow that any attempt to combat that through “heavy social engineering” is necessarily foolish or wrong? Only if all forms of social engineering are foolish or wrong. But they’re not. Lots of forms of deliberate “social engineering” are extremely beneficial (for example, teaching children how to read), and become harmful only when they are accompanied by coercion. If there are independent reasons for thinking that sexual equality is a valuable goal, then even if it is true that social engineering would be required to achieve it, that provides a reason for practicing the social engineering, not a reason for abandoning sexual equality as a goal. If there is some independent reason for rejecting sexual equality as a valuable goal, or for concluding that the costs of the social engineering processes outweigh the benefit to be gained from it, then certainly that’s a reason either to reject anti-sexism in principle or to reject efforts to implement it on a structural level in contemporary life. But you first have to produce those independent reasons; just pointing to some discovery about what human beings may or may not be naturally inclined to do won’t cut the ice you’re trying to cut.